A gas turbine engine typically includes a plurality of shroud and stator vane segments in the turbine stages. Manufacturing and/or assembly tolerance stack-ups, however, typically results in axial mismatch between adjacent shroud segments and adjacent vane segments and/or circumferential misalignment of the shroud segments with the corresponding vane segments.
An example of such mismatch or misalignment is illustrated in FIG. 1 which is a schematic top view of turbine shroud segments 11a, 11b and two stator vane segments 13a and 13b. When a sealed connection between the shroud and the stator vane assemblies is required, the abutting edges 15, 16 of the respective shroud and stator vane segments should abut each other as a seal illustrated between the segments 11b and 13b. However, manufacturing tolerance stack-up typically results in a mismatch between abutting edges 16 of the respective segments 13a, 13b, and sides 20 thus misalign with sides 22 of the segments 11a and 11b. This results in a gap 18 which allows cooling air flowing through the shroud and vane segments to leak into the gas path, thereby causing inefficiency. It is difficult to control such airflow leakage when the engine system is designed because the existence and the dimensions of the gap 18 are essentially random (as tolerances intrinsically are).
Therefore, there is a need for controlling random leakage between the shroud assembly and the stator vane assembly of a gas turbine engine caused by tolerance stack-ups.